(1) Field of the Invention:
The present invention relates to a continuous inorganic fiber consisting of Si, N and O and having excellent properties, and a method of producing the same.
(2) Description of the Prior Art:
There can be obtained Si--N--O inorganic compounds by heating and nitriding SiO.sub.2 at a high temperature in nitrogen, or by reacting SiO.sub.2 with Si.sub.3 N.sub.4 at a high temperature as disclosed by Brosset et al in Nature, Vol. 201 (1964), page 1211, or by Suzuki et al in Yogyo-Kyokai-Shi (Journal of the Ceramic Society of Japan), Vol. 75 (1967), page 111. However, all the resulting Si--N--O inorganic compounds are powders, blocks or wiskers, and an Si--N--O inorganic compound having a continuous fibrous shape has not yet been obtained. A continuous inorganic fiber containing N can be obtained by a method wherein a fiber formed of an organic compound containing N in its molecular structure is fired under an inert gas atmosphere to leave the N contained in the compound in the fired fiber. For example, as disclosed in West German Patent No. 2,218,960, a continuous inorganic fiber containing N can be produced by heating a polycarbosilazane fiber under an inert gas atmosphere. However, in this case, a fiber consisting only of Si, N and O cannot be obtained, but the resulting fiber contains a large amount of C in addition to Si, N and O, and side reactions occur at high temperatures causing deterioration in the properties of the fiber.